A representative experiment depicting the total production of assayable progenitor cells (BFU-E plus CFU-GM, plus CFU-GEMM) in long-term bone marrow cultures initiated with freshly isolated total CD34+ (□) G0CD34+ (⊕), G1CD34+ (•), and CD34+ HLA-DR− CD15− (♦) BM cells. Cultures were maintained by the addition every 48 hours of SCF, IL-3, and IL-6 as described in Materials and Methods. Every week, half of the cultured cells were removed and assayed for clonogenic progenitor cells as described in Materials and Methods. The total production of clonogenic progenitors at every time point was calculated using the formula X = (number of clonogenic cells per culture) ÷ ()n, where “X” is the number of total colonies in culture and “n” is equal to the number of previous demidepopulations. All results were normalized to reflect those obtained from cultures initiated with 104 sorted cells. Identical results were obtained in four other experiments.
